Rewrite:
swimming and running.
Relaxing activities can help people to forget their worries, handle mental pressure, and lower their stress levels.
Many people like relaxing activities because they want to forget their stressful day and because they want to feel relaxed.

Why do we write using this technique?
Using parallelism improves writing style and readability, and makes sentences easier to process.

In science class today, we made our own thermal bottle. By using light reflective material, kids layered their plastic bottle. They also created their own design. Then, we tested the bottles under hot sun by putting ice inside and see if the ice would melt after 5 minutes. Most of the kids had great results!